The present invention relates to transducers, and in particular, relates to improvements in transducers of the type adapted for detecting the interface between two disparate materials and providing a digital signal output representative thereof.
2. Description of the Prior Art
There are a variety of prior art transducers useful for measuring the interface between two disparate materials and providing an electrical signal output representative thereof.
In U.S. Pat. Ser. No. 999,012, Dansinger discloses an aircraft equilibrium device employing a curved tube having a flow mass of metallic pellets therein and sensing electrodes spaced along the tube in order to detect the relative movement of the metal pellets during changes of position while the aircraft is in flight.
Wilkinson, in U.S. Pat. No. 1,106,907, discloses a flow meter employing a conductive fluid, e.g., mercury, in a pressurized tube as a means for allowing current to flow between the sensing electrodes and a point of common potential. The signal output from the sensors then energizes lights to provide means for visually indicating the pressure in the tube.
In U.S. Pat. No. 1,638,814, Epstein shows an arrangement mounted along the flow tube for detecting the rise and fall of a conductive fluid therein.
Hendrickson, in reissue U.S. Pat. Re. No. 19,234, teaches a tilt gauge employing a straight tube having plural electrical contacts associated at opposite ends of the tube. Another tilt gauge arrangement is disclosed by Cole in U.S. Pat. No. 1,974,411.
An arrangement is taught in U.S. Pat. No. 1,978,392 to Brockdorff in which conductive sensors are randomly disposed at varying heights inside a chamber.
A low capacity switch operative when the associated tube or liquid filled container is tilted in an appropriate manner is taught in U.S. Pat. No. 1,982,717 to Wilhelm. A somewhat similar arrangement is disclosed in U.S. Pat. No. 2,935,579 to Fishman. Other tilt gauges and liquid switches are disclosed by Klinger in U.S. Pat. No. 3,372,386 and Eubank in U.S. Pat. No. 3,582,590.
In the arrangements described above, the electrical signal outputs from the sensing means are not readily adaptable to digital data processing techniques.